Various work vehicles, such as motor graders, scrapers, and the like, often work in mountainous terrain where the rate of descent of their work surface is sometimes excessively rapid. It is necessary for the operator to utilize his vehicle braking system in order to maintain adequate control over the vehicle while working on such a relatively steep grade. Where these descending work surfaces are of long lengths, the braking system often experiences an undesirable amount of heat and wear.
It is therefore desirable to provide apparatus and method for controlling the vehicle speed through engine loading with an apparatus that is easily installed on a vehicle expected to be used on steep grades.
This invention therefore resides in apparatus and method for controlling the velocity of an engine driven vehicle having a hydraulic system pump driven by the engine. Means are provided for dividing fluid from the pump into two streams and controllably restricting the flow of the stream relative one to the other and controllably restricting the passage of fluid from the pump for controllably loading the engine through the pump and thereby controlling the velocity of the engine on response thereto.